Utilities that provide gas, electric, water, and/or telephone service bury their conveyances (e.g., pipes and/or cables) underground, both for reasons of safety and aesthetics. Where appropriate, such utilities often provide one or more visual markers along the conveyance right-of-way, alerting those who might potentially excavate of the presence of such a buried conveyance. In some instances, a utility cannot place a sign or marker everywhere along the right-of-way of a buried utility conveyance. Instead, the utility must rely on regulations implemented by many jurisdictions that require contractors contact a central registry for buried utility conveyance information prior to excavation. Contractors that call the central registry receive information identifying buried conveyances in the area of desired excavation. Since the conveyance identity information is often general in nature, most utilities, in response to an inquiry received via the central registry, will dispatch one or more technicians to physically pin-point the buried conveyance to avoid damage by excavation.
Presently, most utilities utilize a radio frequency signaling detection technique to locate buried underground conveyances that carry a locating signal. U.S. Pat. No. 5,644,237, issued Jul. 1, 1997, in the names of Hossein Eslambolchi and John S. Huffman, and assigned to AT&T, discloses a radio frequency signaling detection apparatus for locating buried conveyances. After a utility technician locates a buried conveyance, the technician typically marks the ground above the buried conveyance using a biodegradable paint for this purpose. Different colors are employed to designate different types of conveyances. Telephone service providers typically use orange paint to designate buried telephone cables while gas, water and electric utilities use yellow, blue, and red to designate buried gas, water, and electric conveyances, respectively.
To mark the location of a buried conveyance, the utility technician carries a power paint cartridge or spray can to apply the appropriate color paint. In practice, most utility technicians find it awkward to actuate the power paint cartridge or spray can while using present day radio frequency location equipment. Moreover, even when the technician is able to actuate the paint cartridge or spray can, the resultant color marking, while identifying the type of conveyance, provides no information as to the particular utility responsible for the conveyance.
Thus, there is a need for a technique that allows a utility technician to readily mark the ground above a buried conveyance in a manner that both designates its nature, as well as the entity responsible for its maintenance.